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Subtract a one-digit number

Linked from: Number and Algebra: Whole number operations 95-104

Content strand: Number and Algebra

PAT Maths descriptor: Subtract a one-digit number from a two-digit number.

Curriculum code: ACMNA015


Prerequisites

  • Subtraction strategies 
  • Counting on or counting back for subtraction 

Key concepts and skills

  • Identifying which operation to use in a word problem
  • Subtracting a one-digit number from a two-digit number

Question

Common errors and misconceptions

Key 19
Item commentary This item requires students to identify and link the relevant elements of the information provided; select and apply an appropriate strategy (subtraction); and communicate the result of a calculation as a single numeric result.
A common error may be adding the two numbers in the question.
A common error may be making a subtraction error such as 24 – 5 = 20.
A difficulty may be reading the word 'five' and it is read as a different number.

Linked concept builders

  • Subtraction of one-digit numbers
  • Devising strategies
  • Communication
  • Identifying which operation to use in a word problem

Moving forward

  • Subtraction of ten (Concept builder)